From 63cb4fbbb961da133c68865845eaf22d9b876700 Mon Sep 17 00:00:00 2001
From: chai <chaifix@163.com>
Date: Sun, 27 Sep 2020 20:31:53 +0800
Subject: *misc

---
 src/lua51/lfunc.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

(limited to 'src/lua51/lfunc.c')

diff --git a/src/lua51/lfunc.c b/src/lua51/lfunc.c
index df2c8e3..5835295 100644
--- a/src/lua51/lfunc.c
+++ b/src/lua51/lfunc.c
@@ -32,6 +32,7 @@ Closure *luaF_newCclosure (lua_State *L, int nelems, Table *e) {
 
 //c 新建lua closure
 //c nelems upvalue的个数
+//c 这个方法有两个地方调用，一个是f_parser，在代码编译后生成一个闭包；一个是闭包内嵌方法执行到OP_CLOSURE指令时新建闭包
 Closure *luaF_newLclosure (lua_State *L, int nelems, Table *e) {
   Closure *c = cast(Closure *, luaM_malloc(L, sizeLclosure(nelems)));
   luaC_link(L, obj2gco(c), LUA_TFUNCTION); //c 加入GC链表
@@ -43,7 +44,7 @@ Closure *luaF_newLclosure (lua_State *L, int nelems, Table *e) {
 }
 
 
-//c 新建一个closed upvalue
+//c 新建一个upvalue，默认是closed
 UpVal *luaF_newupval (lua_State *L) {
   UpVal *uv = luaM_new(L, UpVal);
   luaC_link(L, obj2gco(uv), LUA_TUPVAL); //c 加入GC链表
@@ -53,6 +54,7 @@ UpVal *luaF_newupval (lua_State *L) {
 }
 
 
+//c 设置upvalue的数据指针指向stack中某个值level
 UpVal *luaF_findupval (lua_State *L, StkId level) {
   global_State *g = G(L);
   GCObject **pp = &L->openupval;
@@ -82,6 +84,7 @@ UpVal *luaF_findupval (lua_State *L, StkId level) {
 }
 
 
+// 把uv从global_state->uvhead或者lua_state->openupval中删除
 static void unlinkupval (UpVal *uv) {
   lua_assert(uv->u.l.next->u.l.prev == uv && uv->u.l.prev->u.l.next == uv);
   uv->u.l.next->u.l.prev = uv->u.l.prev;  /* remove from `uvhead' list */
@@ -89,6 +92,7 @@ static void unlinkupval (UpVal *uv) {
 }
 
 
+//c 从global_state->uvhead中删除并释放内存
 void luaF_freeupval (lua_State *L, UpVal *uv) {
   if (uv->v != &uv->u.value)  /* is it open? */
     unlinkupval(uv);  /* remove from open list */
@@ -96,19 +100,23 @@ void luaF_freeupval (lua_State *L, UpVal *uv) {
 }
 
 
+//c 设置闭包的upvalue
 void luaF_close (lua_State *L, StkId level) {
+	log("luaF_close()");
   UpVal *uv;
   global_State *g = G(L);
   while (L->openupval != NULL && (uv = ngcotouv(L->openupval))->v >= level) {
     GCObject *o = obj2gco(uv);
-    lua_assert(!isblack(o) && uv->v != &uv->u.value);
+    lua_assert(!isblack(o) && uv->v != &uv->u.value);  //必须是 open upvalue
     L->openupval = uv->next;  /* remove from `open' list */
-    if (isdead(g, o))
+    if (isdead(g, o)) 
       luaF_freeupval(L, uv);  /* free upvalue */
-    else {
-      unlinkupval(uv);
-      setobj(L, &uv->u.value, uv->v);
+    else { 
+      unlinkupval(uv); // 从L->openupval中删除
+
+      setobj(L, &uv->u.value, uv->v);  // 拷贝到upvalue的value字段，upvalue储存值
       uv->v = &uv->u.value;  /* now current value lives here */
+
       luaC_linkupval(L, uv);  /* link upvalue into `gcroot' list */
     }
   }
-- 
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